If you only visit one church in Kraków, make it St. Francis Basilica. Built in the 13th century, St. Francis' was the first brick building in Kraków, but its legacy was forged at turn of the century when local artistic genius Stanisław Wyspiański filled the interior with colourful Art Nouveau murals that deftly balance the organic and geometric with unique floral patterns. Wyspiański also designed the church's magnificent stained glass windows, including the imposing, almost violently energetic ‘God in the Act of Creation’ window over its rear entrance. Argued by some to be the greatest modern stained glass window in the world, it is certainly a must-see for all visitors to Kraków.